1. Field of the Invention
The present invention generally relates to television distribution systems such as cable television (CATV) and multipoint distribution service (MDS) and, more particularly, to an installation and initialization technique which allows a nontechnically trained installer to quickly and accurately load any number of variable items into nonvolatile memory in a set top converter.
2. Description of the Prior Art
Modern CATV and MDS systems employ subscriber converters which can accept and process digital data emanating from an addressing computer in the head end of the distribution system. The digital data conveys commands which can enable and disable a converter, control the availability for viewing of channels and implement other ancillary functions. Addressable converters store digital data in an internal memory which defines the converter address and level of service to be provided to the subscriber.
Existing converters have a number of disadvantages. Establishing an address for the converter is a time consuming and expensive procedure to the manufacturer of the converter and the cable operator. Two basic approaches have been used. One approach is for the manufacturer of the converter to program data into non-volatile memory to store converter addresses. Another approach is for the manufacturer to ship converters to television distribution system operators without addresses assigned. The system operators, in turn, must then unpack the converters, remove converter covers, remove memory integrated circuits (ICs) from the converters and insert them in a programming fixture to insert the address codes, and then to reassemble the converters prior to installation in individual homes. This procedure is labor intensive and raises the possibility of damage to the ICs and the converter itself. Furthermore, the system operator is required to maintain very accurate records of the assigned addresses so that the correlation between a given address and a subscriber installation can be verified and that duplicate address assignments do not occur.
One solution to this problem is described in U.S. Pat. No. 4,760,597 to Hayes et al., now assigned to the assignee of this application. According to that invention, a technician set-up unit is used with an addressable television signal converter having a radio frequency (RF) input port and a data port and that is responsive to a television signal distribution system to be remotely controlled by an addressing computer. The technician set-up unit includes an RF input port for receiving RF coded command signals from the addressing computer. An RF output port is provided which is connectable to the RF input port of the converter. A data port is connectable to the data port of the converter for receiving digital data signals from and sending digital data signals to the converter. The technician set-up unit includes control means responsive to the RF coded command signals for coordinating the exchange of RF and digital data signals between the converter and the technician set-up unit through the respective connected RF and data ports.
In operation, the Hayes et al. technician set-up unit forms a hardware link between the converter and the addressing computer. Data is downloaded to the converter by the addressing computer to define the converter address and to establish the appropriate level of service. The technician set-up unit interrupts RF signals to the RF input port of the converter and inputs data from the addressing computer to the data port of the converter. The converter address data is loaded into the converter memory upon reinstatement of the RF addressing commands to the converter. The data which has been stored in the converter is subsequently read to verify proper installation. When the installation is verified, a final command is sent to the converter to render it operational. If verification fails, the converter is rendered inoperative.
While the Hayes et al. technician set-up unit and the procedures employed represent a significant improvement over the prior art, it nevertheless suffers some disadvantages. Specifically, the unit must be interconnected with the converter and installation must be correlated with the addressing computer at the head end of the distribution system. The interconnection of the unit with the converter and the subsequent operation of the unit require a certain level of skill and training of the installer. Moreover, it may not always be convenient or possible to arbitrarily correlate the installation process with the addressing computer.